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Biomedical subjects

M Ohji

Publications and source records attributed to M Ohji.

At least 19 recordsLinked to original sources
PubMed2006

Pars plana vitrectomy with peripheral retinotomy after injection of preoperative intravitreal tissue plasminogen activator: a modified procedure to drain massive subretinal haemorrhage.

AIMS: To report outcome of a modified procedure for draining massive subretinal haemorrhages (SRHs). METHODS: The charts of eight consecutive eyes from eight patients with massive SRHs extending to the periphery and involving two or more quadrants with haemorrhagic and bullous retinal detachment were reviewed. Tissue plasminogen activator (tPA) was injected intravitreally 12-24 h preoperatively; vitrectomy was carried out with peripheral retinotomy, drainage of the SRH from the retinotomy using perfluorocarbon liquid and gas tamponade with prone positioning postoperatively. RESULTS: The preoperative visual acuities ranged from light perception to 20/200. Most of the subretinal haematomas moved postoperatively to the vitreous cavity through the peripheral retinotomy using perfluorocarbon liquid. Residual SRHs were drained from the anterior chamber at the bedside after prone positioning overnight. SRH recurred in one eye 14 months postoperatively and was successfully retreated. No other serious complications developed. The final visual acuity improved in seven eyes (range 20/1000-20/60). Polypoidal lesions in choroidal vasculatures were present in three of seven patients. CONCLUSIONS: The technique seems safe and effective for treating massive SRH. However, visual recovery is limited by the underlying macular pathology. Polypoidal choroidal vasculopathy, other than age-related macular degeneration, may be another cause of massive SRHs.

Aged↗
PubMed2005

Choroidal neovascularisation in pathological myopia: an update in management.

Choroidal neovascularisation (CNV) secondary to pathological myopia is an important cause of significant visual impairment in young and middle aged adults globally and is particularly prevalent in Asian populations. In the past few years, there have been rapid advancements in the different treatments for myopic CNV. The purpose of this perspective is to give an overview of the natural history of myopic CNV and the various treatment options including laser photocoagulation, photodynamic therapy, sub-macular surgery, and macular translocation surgery. Future directions in the management of myopic CNV are also discussed.

Choroidal Neovascularization↗
PubMed2004

Application of femtosecond ultrashort pulse laser to photodynamic therapy mediated by indocyanine green.

BACKGROUND/AIMS: To evaluate treatment with high peak power pulse energy by femtosecond ultrashort pulse laser (titanium sapphire laser) delivered at an 800 nm wavelength for corneal neovascularisation using photodynamic therapy (PDT) mediated by indocyanine green (ICG). METHODS: Using a gelatin solid as an in vitro corneal model, the safety of laser power was studied to determine if it degenerated gelatin with or without ICG. The authors then induced corneal neovascularisation in rabbit eyes by an intracorneal suturing technique. Fluorescein angiography was used to evaluate occlusion before PDT and 0, 1, 3, and 10 days after PDT. The authors performed light microscopy with haematoxylin eosin staining and transmission electron microscopy to determine thrombosis formation in the neovascular regions. RESULTS: The threshold of peak laser power density ranged from 39 to 53 W/cm(2). Laser irradiation was started 30 seconds after a 10 mg/kg ICG injection, and all irradiated segments were occluded at 0, 1, 3, and 10 days at 3.8 J/cm(2). Light and electron microscopy documented thrombosis formation in the neovascular region. CONCLUSION: Femtosecond pulse laser enhanced by ICG can be used for PDT. Because of effective closure of corneal neovascularisation at a low energy level, the high peak power pulse energy of the femtosecond pulse laser might be more efficacious than continuous wave laser for use with PDT.

Animals↗
PubMed2001

Topographic analysis of astigmatism induced by scleral shortening in pig eyes.

BACKGROUND: Corneal astigmatism is a severe postoperative problem in foveal translocation surgery. We evaluated the corneal astigmatism induced by scleral shortening in pig eyes in vitro. METHODS: We created three sizes of scleral shortening in pig eyes and examined the preoperative and postoperative corneal astigmatism. The three sizes of scleral shortening were; 6 mm x 12 mm, 9 mm x 12 mm, and 6 mm x 16 mm (radial x circumferential). The shortenings were created 11 mm from the limbus with 10 eyes in each group. Videokeratographic measurements were performed using the CAS System 2000, preoperatively and postoperatively, and the astigmatism caused by the scleral shortening was evaluated. RESULTS: The surgically-induced astigmatism was 2.1 +/- 1.2 diopters (D) in the 6 mm x 12 mm group, 5.2+/-1.5 D in the 9 mm x 12 mm group, and 3.7+/-1.0 D in the 6 mm x 16 mm group. Corneal astigmatism caused by scleral shortening depended on both the radial and circumferential shortening. Pre- and postoperative topographic corneal maps showed an irregular astigmatism pattern (lazy bowtie pattern). Because the central zone of the cornea showed a relatively regular astigmatism, the corneal astigmatism induced by scleral shortening did not affect the predicted corneal acuity. CONCLUSIONS: In foveal translocation surgery with scleral shortening, an excessive scleral resection in the radial direction can cause clinically intolerable regular and irregular astigmatism. Minimal scleral shortening that will satisfy the required translocated distance is recommended to reduce the risk/benefit ratio.

Animals↗
PubMed2001

Visual function after foveal translocation with 360-degree retinotomy and simultaneous torsional muscle surgery in patients with myopic neovascular maculopathy.

PURPOSE: To assess functional and anatomical outcomes after foveal translocation with 360-degree retinotomy and simultaneous torsional muscle surgery in patients with myopic neovascular maculopathy. METHODS: Foveal translocation with 360-degree retinotomy was performed in 11 eyes of 11 patients with myopic neovascular maculopathy. Ten eyes had simultaneous torsional muscle surgery with recession of the superior oblique muscle and tucking of the inferior oblique muscle. Silicone oil removal with or without intraocular lens implantation was performed 2 to 8 weeks after the primary procedure. Visual acuity, binocular function, and degree of cyclotorsion were assessed preoperatively and postoperatively. Angles of retinal and globe rotation, distance of foveal shift, and surgical complications were also investigated. RESULTS: With a mean postoperative follow-up of 6.2 months (range, 3 to 13 months), vision improved (greater than 0.2 logarithm of minimal angle of resolution [logMAR] units) in eight eyes, was unchanged in two eyes, and worsened (greater than 0.2 logMAR units) in 1 eye. Seven of 11 eyes (64%) had a final visual acuity of 20/50 or better. Five patients developed or maintained binocular fusion, four patients continued to have suppression, and two patients developed diplopia that was managed by spectacles with Fresnel prisms. Subjective cyclotorsion was less than 8 degrees in 10 eyes. Mean retinal and globe rotations were 23.4 degrees and 19.8 degrees, respectively. Average size of the choroidal neovascular membrane was 0.8 disk diameter, whereas the average distance of foveal shift was 1.5 disk diameter. After the primary procedure, three eyes developed retinal detachment, one eye macular hole, and one eye proliferative vitreoretinopathy. These complications were successfully managed by additional surgery. CONCLUSION: Foveal translocation with 360-degree retinotomy is effective in restoring vision in some patients with myopic neovascular maculopathy. Although the development of torsional diplopia is generally obviated by simultaneous extraocular muscle surgery, a relatively high incidence of surgical complications should be taken into account with this procedure.

Aged↗
PubMed2001

Indocyanine green facilitates removal of epiretinal and internal limiting membranes in myopic eyes with retinal detachment.

PURPOSE: To describe the use of intravitreal indocyanine green as an aid to identifying epiretinal membranes and internal-limiting membranes during surgery for a retinal detachment resulting from a macular hole. METHODS: A 62-year-old man who had a retinal detachment resulting from a macular hole underwent vitrectomy. During the surgery, intravitreal indocyanine green was injected intravitreally. RESULTS: The internal-limiting membrane was stained green, but the epiretinal membrane was unstained. Because the epiretinal membrane and internal-limiting membrane were clearly identified, they could be completely removed. The clinical observations of the epiretinal membrane and internal-limiting membrane excised were confirmed by electron microscopy. Successful reattachment was obtained without damage to the retina. CONCLUSION: Removal of epiretinal membrane and internal-limiting membrane can be facilitated by using intravitreal indocyanine green during vitrectomy. We recommend further studies to confirm the benefit of this technique.

Basement Membrane↗
PubMed2001

Effect of Ca(2+)-free and Mg(2+)-free BSS Plus solution on the retinal pigment epithelium and retina in rabbits.

PURPOSE: To determine whether intravitreal irrigation with Ca(2+)-free and Mg(2+)-free BSS Plus (Alcon Laboratory, Fort Worth, Texas) solution alters the adhesiveness between the retinal pigment epithelium and the retina of rabbits. METHODS: Thirty-four eyes of 34 Dutch pigmented rabbits underwent lensectomy and vitrectomy. Subsequently, the vitreous cavity of 24 eyes was irrigated with Ca(2+)-free and Mg(2+)-free BSS Plus solution for 10 or 20 minutes. The other 10 eyes were irrigated with BSS Plus solution for 20 minutes as controls. To determine the adhesiveness between the retinal pigment epithelium and retina, a retinal detachment was produced in 12 of the 34 eyes. The apical surface of the retinal pigment epithelium and the photoreceptor outer segments were examined by scanning electron microscopy. Retinal physiology was assessed by electroretinography and retinal morphology by light microscopy. RESULTS: After retinal detachment was produced, the number of cone sheaths on the apical surface of the retinal pigment epithelium after irrigation with Ca(2+)-free and Mg(2+)-free BSS Plus solution for 20 minutes (33 +/- 15, mean +/- SD) was significantly less than the number of cone sheaths on the apical surface of the retinal pigment epithelium of eyes after irrigation with BSS Plus solution for 20 minutes (120 +/- 50) or the number of cone sheaths on the apical surface of the retinal pigment epithelium of eyes after 10 minutes of irrigation with Ca(2+)-free and Mg(2+)-free BSS Plus solution (115 +/- 49; P =.02). The b-wave amplitudes in the eyes irrigated with Ca(2+)-free and Mg(2+)-free BSS Plus solution for 20 minutes were depressed compared with the b-waves in eyes irrigated with BSS Plus solution for 20 minutes on the first postoperative day (P =.03). After the third postoperative day, there was no significant difference in the b-waves (P >.06). Light microscopy demonstrated no morphologic abnormalities after the use of both solutions. CONCLUSIONS: Intravitreal irrigation with Ca(2+)-free and Mg(2+)-free BSS Plus solution for 20 minutes altered the adhesion between the retinal pigment epithelium microvilli and retinal outer segments and made the creation of retinal detachment less traumatic. These results suggest that Ca(2+)-free and Mg(2+)-free BSS Plus solution may be of clinical value for the creation of an intentional retinal detachment for foveal translocation surgery.

Animals↗
PubMed2001

Assessment of nuclear sclerosis after nonvitrectomizing vitreous surgery.

PURPOSE: Nuclear sclerosis develops frequently after successful pars plana vitrectomy. We evaluated changes in the degree of nuclear sclerosis after nonvitrectomizing vitreous surgery for idiopathic epimacular proliferation. METHODS: Forty-one consecutive patients (41 eyes) underwent removal of idiopathic epimacular proliferation by nonvitrectomizing vitreous surgery and were followed postoperatively for at least 12 months. Visual acuity, refractive error, slit-lamp biomicroscopy, and Scheimpflug photographs were assessed preoperatively and postoperatively to evaluate changes in the degree of lenticular opacification. Quantitative analysis of the nuclear sclerosis was performed by densitometry with Scheimpflug photographs performed on only the last 21 patients. We evaluated these measurements by comparing statistically the preoperative and postoperative difference between both eyes (operative eye minus nonoperative ocular data). RESULTS: There was no significant difference in the progression of nuclear sclerosis or degree of myopic shift between the operated and fellow eyes during postoperative follow-up (mean +/- SD, 22 +/- 8 months; median, 22 months; range, 12 to 48 months). The average preoperative and postoperative refractive errors in operated eyes were 0.0 +/- 2.4 diopters and 0.1 +/- 2.5 diopters, respectively; the average difference in the refractive errors between both eyes was -0.2 +/- 0.7 diopter preoperatively and -0.2 +/- 0.9 diopter postoperatively (P =.961, paired t test). The average preoperative and postoperative nuclear density values by Scheimpflug photography in 21 operated eyes were, respectively, 72 +/- 18 nuclear density units and 75 +/- 17 nuclear density units; the average difference in nuclear density values between both eyes was -1 +/- 4 nuclear density units preoperatively and 0 +/- 6 nuclear density units postoperatively (P =.631, paired t test). CONCLUSION: Progression of nuclear sclerotic cataract based on changes in refractive error and Scheimpflug photography was not observed after nonvitrectomizing vitreous surgery.

Aged↗
PubMed2001

Evaluation of the peripheral visual field after foveal translocation.

PURPOSE: To evaluate the peripheral visual field after foveal translocation with scleral imbrication or 360-degree retinotomy. METHODS: Retrospective, single-center, nonrandomized study. We calculated the rate of preservation of the peripheral visual field using Goldmann perimetry by dividing the width of the postoperative V-4 isopter by the preoperative width and expressing the result as a percentage. RESULTS: In nine eyes that underwent scleral imbrication, the rate of preservation was 100.0% superiorly, 102.6% superotemporally, 99.9% temporally, 97.9% inferotemporally, 96.9% inferiorly, 82.3% inferonasally, 93.7% nasally, and 87.3% superonasally. In 33 eyes that underwent 360-degree retinotomy, it was 89.1%, 87.0%, 81.9%, 78.1%, 86.6%, 90.0%, 89.9%, and 86.8%, respectively. CONCLUSION: After foveal translocation with scleral imbrication, the peripheral visual field was preserved except for slight narrowing nasally; 360-degree retinotomy resulted in preservation of the visual field, except for slight narrowing in all meridians.

Aged↗
PubMed2001

Comparison of three techniques of foveal translocation in patients with subfoveal choroidal neovascularization resulting from age-related macular degeneration.

PURPOSE: To report the results of three methods of foveal translocation in the presence of subfoveal choroidal neovascular membrane resulting from age-related macular degeneration. METHODS: We treated 51 eyes of 51 consecutive patients with subfoveal choroidal neovascular membranes resulting from age-related macular degeneration with one of three techniques of foveal translocation surgery: foveal translocation with partial retinotomy (n = 6), limited translocation (n = 9), and translocation with 360-degree retinotomy (n = 36). All patients were followed for at least 6 months postoperatively. The size of the choroidal neovascular membrane and the amount of foveal displacement, the best-corrected visual acuity, and complications were recorded preoperatively and postoperatively. RESULTS: The mean distance of the foveal translocation was greater in the 360-degree retinotomy group (3340 microm) than in the partial retinotomy (1060 microm, P <.001) and the limited translocation groups (1120 microm, P <.001). A final visual acuity of 20/200 or better was achieved in two eyes (33%) in the partial retinotomy group, seven eyes (78%) in the limited translocation group, and 23 eyes (64%) in the 360-degree retinotomy group. The final visual acuity improved by 0.2 logarithm of minimal angle of resolution (logMAR) unit or more in one eye (17%), one eye (11%), and seven eyes (19%), respectively. The final visual acuity was maintained within 1 line in zero eyes, five eyes (56%), and 19 eyes (53%), respectively. A retinal detachment developed postoperatively in five eyes (83%), zero eyes (0%), and 15 eyes (42%), respectively. CONCLUSIONS: A significant number of patients improved or maintained best-corrected visual acuity after translocation with 360-degree retinotomy, and limited translocation, whereas translocation with 360-degree retinotomy is suitable for larger choroidal neovascular membranes because it resulted in the greatest foveal displacement among the three translocation procedures.

Aged↗
PubMed2000

The visual performance and metamorphopsia of patients with macular holes.

BACKGROUND: Most patients attain better visual acuity with the elimination of metamorphopsia after successful closure of a macular hole (MH) by vitrectomy. OBJECTIVE: To determine the presurgical visual function of eyes with an MH. METHODS: We examined 54 eyes of 51 patients with an idiopathic MH using the Amsler chart. We evaluated the types of subjective metamorphopsia and compared them with the clinical factors associated with MHs. In a prospective study, we performed a montage test on a separate group of 16 patients with unilateral idiopathic MHs. The patients were asked to choose, while viewing with their better eye, the computer-modified picture that best matched the unmodified image seen by the eye with the MH. RESULTS: From the results of the Amsler chart test, we divided the subjective changes into 2 types of metamorphopsia; of the 54 eyes, pincushion distortion (bowed toward the center) was found in 33 (61%), and unpatterned distortion (no specific pattern) was found in 21 (39%). Pincushion distortion was significantly associated with an MH of shorter duration (< or =6 months) (P = .03) and an early stage (stage 2) of MH formation (P = .02). A scotoma was hard to detect, and patients had difficulty describing their scotomata and distortions. In the montage test, patients with early MHs chose portraits modified with a pincushion type of distortion. CONCLUSIONS: We found concentric pincushion metamorphopsia without subjective scotomata, which we suggest arises from an eccentric displacement of the photoreceptors. This accounts for the main characteristic of the visual performance of patients with idiopathic MHs.

Aged↗
PubMed2000

New soft-tipped instruments for foveal translocation surgery with 360 degrees retinotomy.

Foveal translocation surgery with 360 degrees retinotomy involves several surgical procedures, including creation of a total retinal detachment, rotation of the retina, and complete reattachment of the retina. Some of these procedures, which are time-consuming and difficult to perform, may damage the retina when conventional surgical instruments are used. To make these procedures safer and easier, we have developed 3 soft instruments: an atraumatic forceps, a modified Chang double-barrel cannula with a silicone tip, and a light pipe with a silicone tip. The atraumatic forceps allows the surgeon to grasp and peel off the retina with less damage during the creation of retinal detachment. A bimanual technique using the other 2 instruments allows surgeons to rotate and reattach the detached retina easily and safely. We believe that these soft-tipped instruments make foveal translocation a less complicated surgery.

Choroidal Neovascularization↗
PubMed2000

Amsler grid examination and optical coherence tomography of a macular hole caused by accidental Nd:YAG laser injury.

PURPOSE: To compare a macular hole from accidental Nd:YAG laser injury with idiopathic macular holes. METHODS: Case report. In a 24-year-old man with accidental Nd:YAG laser injury, right eye, Amsler grid testing and optical coherence tomography were performed. RESULTS: Nd:YAG laser injury was responsible for a macular hole about 700 microm in diameter. The visual acuity was 20/100. Amsler grid testing displayed a central scotoma with no surrounding distortion. Optical coherence tomography showed a defect in all retinal layers at the macula. CONCLUSION: The scotoma caused by Nd:YAG laser injury is not surrounded by distortion; the hole is produced by the defect of all retinal layers. In contrast, idiopathic macular holes generally produce a pincushion pattern on Amsler grid testing and have no tissue loss.

Accidents, Occupational↗
PubMed2000

Comparison of visual function after foveal translocation with 360 degrees retinotomy and with scleral shortening in a patient with bilateral myopic neovascular maculopathy.

PURPOSE: To compare the visual outcome after foveal translocation by scleral shortening and that after 360 degrees retinotomy with extraocular muscle surgery in a patient with bilateral myopic neovascular maculopathy. METHODS: Case report. RESULTS: A 52-year-old woman with bilateral myopic neovascular maculopathy underwent foveal translocation with scleral shortening in the left eye, and visual acuity improved from 20/70 to 20/30. However, choroidal neovascularization recurred, and the final visual acuity was 20/40 after excision of the choroidal neovascularization. Foveal translocation with 360 degrees retinotomy was performed on the right eye, and visual acuity improved from 20/150 to 20/30. The critical print size was better, and the retinal sensitive area was larger in the right eye. CONCLUSION: The better reading ability shown by foveal translocation by a 360 degrees retinotomy compared with scleral shortening may stem from a larger retinal sensitive area obtained by this method.

Choroidal Neovascularization↗